Conventionally, hair dye compositions in a liquid or cream form have been in widespread use, but it is difficult to evenly apply those compositions to the head hair. In particular, consumers must acquire skills, such as blocking or two mirror technique, to apply the compositions evenly to the root portions of the head hair or to the head hair of an occipital region of the head by themselves, and must carry out operations carefully to apply the compositions evenly.
In view of the foregoing, it has been proposed to simplify hair dyeing operations by discharging an agent as a foam, and for example, a two-part aerosol type and a one-part non-aerosol type have been known. However, the two-part aerosol type composition involves problems in that uneven bleaching and uneven dyeing are likely to occur because the mixing ratio of a first part and a second part does not become constant, a pressure-resistant container and the like made of a metal are oxidized and corroded by hydrogen peroxide, and the internal pressure in the pressure-resistant container is excessively increased owing to the decomposition of hydrogen peroxide. Further, one part non-aerosol type composition involves a problem in that the one part non-aerosol type composition shows no or little bleaching ability enough to cause substantial color tone change in a single application, thereby leaving the composition for a long period of time after the application, or repetitive application of the composition is necessary, resulting in the hair dyeing operations being complicated.
In contrast to the above, products characterized in that a two-part hair dye composition is discharged as a foam from a non-aerosol type foamer container have been proposed (see Patent Documents 1 and 2). In those products, through the discharge of a liquid mixture of a first part and a second part as a foam from a foamer container, the variations of mixing ratio hardly occur compared to the conventional two-part non-aerosol type products, and sufficient bleaching ability or hair dyeing ability may be provided compared to the conventional one part non-aerosol type products.
However, in order to foam a liquid mixture with a non-aerosol type foamer container, the liquid mixture must have a low viscosity, and at the same time, the liquid mixture must be prevented from dripping when being applied to the hair.
Patent Documents 1 and 2 disclose a method of incorporating a higher alcohol to prevent a liquid mixture from dripping. However, in the case of a higher alcohol being used, the problem is that, viscosity of the liquid mixture increases when the liquid temperature is low, for example, in winter season, thereby foaming the liquid mixture with a foamer container being difficult.    [Patent Document 1] JP-A-2004-339216    [Patent Document 2] JP-A-2006-124279